No, the strongest candidate certainly was McCain. Giuliani was hated by the base (Although McCain was disliked, he wasn't as liberal as Giuliani and was acceptable), Romney had the businessman shtick, during the worst economic catastrophe since the 1930s he would have been destroyed. Huckabee was likeable, but the polls showed him losing by double digits, only really appealed to the evangelicals, and is disliked by much of the mainstream conservatives.
Really, McCain, a war hero with tremendous experience, was the only one of the candidates who ran could win.
McCain couldn't even run a campaign, let alone the country. In fact, if my state wasn't a guaranteed lock for Obama, I have no idea where my vote would have gone.